What is Sany Excavator Fault Code P2146?

Fault Code P2146 indicates "Fuel Injector Group 'A' Supply Voltage Circuit/Open," signaling that the Engine Control Module (ECM) has detected an abnormal voltage condition or open circuit in the fuel injector supply circuit for cylinder bank A. This code is part of the OBD-II diagnostic standard and specifically relates to the power supply circuit that energizes the fuel injectors, rather than the injectors themselves.

In Sany excavators, this fault affects the fuel injection system's ability to deliver precise fuel quantities to the combustion chambers. The ECM monitors the injector driver circuit continuously, and when voltage readings fall outside predetermined parameters (typically 10-14 volts during operation), P2146 triggers. This is critical because improper injector voltage directly compromises engine performance, fuel efficiency, and emissions compliance, particularly problematic in used machines where electrical degradation is common.

Common Symptoms

• Check Engine Light illuminated on the instrument cluster with possible engine derate mode activated
• Rough idling, misfiring, or noticeable power loss during operation, especially under load
• Difficulty starting the engine, particularly cold starts requiring extended cranking
• Increased black or white smoke from the exhaust due to incomplete combustion
• Reduced hydraulic system performance as engine RPM fluctuates inconsistently

Potential Causes

The most frequent causes of P2146 in used Sany excavators include:

• Damaged wiring harness or corroded connectors in the injector supply circuit, particularly at rub points near the engine block or valve cover
• Faulty injector driver relay or blown fuses in the fuel injection power supply system
• Failed ECM internal injector driver circuits due to age-related component degradation
• Low battery voltage or failing alternator not maintaining adequate charging system voltage (below 12.5V)
• Aftermarket electrical modifications or improper repairs disrupting factory wiring integrity
• Corroded ground connections affecting the injector circuit return path

How to Troubleshoot and Fix Code P2146

Step 1: Visual Inspection Begin by thoroughly inspecting the injector wiring harness from the ECM to each injector connector on cylinder bank A. Look for chafed insulation, pinched wires at mounting brackets, or greenish corrosion inside connector bodies—common issues in used excavators exposed to moisture and vibration.

Step 2: Voltage Testing Using a digital multimeter, check supply voltage at the injector harness connector with ignition ON, engine OFF. You should read battery voltage (12-14V). If voltage is absent, trace back to the injector relay and fuses, testing continuity through each component.

Step 3: ECM and Ground Verification Test the ECM injector driver output using Sany diagnostic software or a compatible scan tool capable of actuating injectors. Simultaneously verify all engine ground straps show less than 0.5 ohms resistance to battery negative. In used machines, ground corrosion frequently causes phantom electrical faults.

Step 4: Component Replacement If wiring and voltage checks pass, suspect ECM internal failure. Before replacing the expensive ECM, swap the injector relay with an identical relay from another circuit to rule out relay failure—a common and inexpensive fix.

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Disclaimer: This guide provides general troubleshooting information. Always consult Sany service manuals and consider professional diagnostic assistance for complex electrical issues, especially when working with used equipment where multiple underlying problems may exist.